There is a kind of insulation displacement connectors having insulation displacement terminals, supplied by a maker to a user after being sub-assembled, and connected via the insulation displacement terminals to electrical wire on the user side before using. Generally, connecting methods have been required for such insulation displacement connectors, which are easily connectable while maintaining a high reliability of electrical connection. It is important for the purpose of enhancing the reliability of electrical connection that the electrical wire does not slide out of the connector when an unintentional external force is applied to the electrical wire, and for the purpose of facilitating the ease of electrical connection that the mutual connection between the electrical wire and the terminal is possible with a small amount of labor providing favorable operability.
One example of such kinds of insulation displacement connectors is disclosed in Japanese Unexamined Patent Publication No. 2003-173827. As shown in FIG. 11, this insulation displacement connector 60 includes insulation displacement terminal 61 having a wire insulation displacement portion 61a formed by cutting and folding for electrical connection to a core wire of an electrical wire 67, a connector housing 62 for holding the insulation displacement terminal 61 and having an opening 62a at a position corresponding to the wire insulation displacement portion 61a of the insulation displacement terminal 61, and a wire holder 63 having a pair of upper and lower covers 64, 65 assembled to each other by being pushed into the opening 62a so that the electrical wire 67 is held between the pair of upper and lower covers 64, 65. Crank-like stepped portions 64a and 65a are formed on the opposite surfaces of the covers 64, 65 at a wire-inserting end thereof so that the electrical wire 67 is carved to be a crank shape by the stepped portions 64a and 65a when the upper and lower covers 64, 65 are assembled with each other, whereby the electrical wire 67 is not unintentionally slid out of the wire holder 63.
In the insulation displacement connector 60 disclosed in Japanese Unexamined Patent Publication No. 2003-173827, as a wire inserting opening 66 on a wire-inserting side of the wire holder 63 becomes narrow due to the crank-shaped stepped portions 64a, 65a, a careful operation is necessary when the electrical wire 67, which has a tendency of twisting or bending, is inserted, so that the inserted end of the electrical wire is not brought into contact with the stepped portions 64a and 65a. Also, size of the electrical wire is limited to facilitate the insertion of the electrical wire 67 into the wire holder 63 and to prevent the electrical wire 67 from sliding out of the connector. When thin electrical wire (small-diameter wire), particularly those having an outer diameter of 1 mm or less are used, a wire clamping-force is weak in the wire insulation displacement portion and therefore, a connector capable of more assuredly clamping the wire has been required.